1. Field of the Invention
This invention relates to a piston for internal combustion engines, comprising a rotational-symmetric barrel carrying the piston rings, with a bottom piece which on one side is configured as a supporting cone tapering towards the two piston pin bosses placed at a distance from each other, and on the other side as a combustion recess, the supporting cone and the piston pin bosses being joined by supporting elements cast integral with the former, and further comprising a guide shoe or piston skirt.
2. Description of the Prior Art
A one-piece piston of this type is known, which is characterized by the disadvantage that the guide shoe and the rest of the piston cannot be made from different materials, for example, iron and aluminium. The main disadvantage of this piston, however, is its tendency to deteriorate or fail under its high thermal and mechanical operating loads. In this piston the extremely high pressure loads of the piston bottom are transmitted via a supporting base in the shape of a hollow cylinder attached to the piston bottom, which extends downwardly from the piston bottom to the piston pin bosses, the only exception to its cylindrical form being two curved openings between the bosses situated at an angle of 90 degrees to the boss-axis. The flexural stiffness of the piston thus is approximately the same both in the direction of the piston axis and in the direction normal to this axis, with the consequence that during operation the piston is subject to undesirable deformations in the direction normal to the piston pin axis, or - if this is to be avoided - that the overall dimensions of the piston must be increased. This kind of support of the piston bottom also results in an undesirably high degree of heat transfer between piston bottom and piston pin bosses, which ideally should be kept as small as possible.